Rice seed caoted with an agriculture chemical

ABSTRACT

The invention provides a rice seed coated with an agricultural chemical, characterized in that a rice seed is deprived of husk and the surface of said rice seed is coated with a binder containing an agricultural chemical. The rice seed is suitable to be germinated by maintaining the seed for at least three days at 20 to 40 degrees C.

FIELD OF THE INVENTION

[0001] This invention relates to rice seeds coated with an agriculturalchemical.

BACKGROUND OF THE INVENTION

[0002] In order to protect rice seeds or seedling from diseases causedby fungi or bacteria, intact rice seeds in the husk are conventionallysoaked in a solution of one or more fungicidal and/or bactericidalagents before sowed. However, this process can not fully preventdiseases caused by fungi or bacteria. Moreover, this process has apollution problem caused by discharge of the solution of the fungicidaland/or bactericidal agent after seed soaking as well as an economicalproblem by loss of the fungicidal or bactericidal agent. Furthermore, inorder to completely prevent damage caused by the fungi after sowing, thefungicidal agent is needed to be applied again after sowing. Also inorder to prevent damage by insects after sowing, the sprinkling of theinsecticidal agent is needed.

[0003] Coating intact rice seeds with a fungicidal or bactericidal agentwas performed for the purpose of solving the above-mentioned problems.However, this could not sufficiently solve the problems.

[0004] Beside, in order to germinate intact rice seeds, it is necessaryto have the seeds first absorb enough water. Thus, intact rice seedsneed to be kept under water for a considerable time period to absorbenough water through the husk before sowing so as to attain uniformsprouting, because the outside of the seeds is covered by the husk.

[0005] In the conventional technology, intact rice seeds with husk arecoated, on the husk, with a binder which contains an agriculturalchemical, and are soaked in water containing one or more fungicidal orbactericidal agents for about one day to sterilize adhering fungi orbacteria. Subsequently, the water containing the fungicidal orbactericidal agents is replaced with fresh water. Then, one waits fordevelopment of the sprout of rice seeds, while circulating optionallyheated water through the mass of rice seeds.

[0006] Rice seeds usually start sprouting and developing the coleoptileof the embryo in about three days after the start of circulation ofwater, and come into a so-called “pigeon breast” state. The rice seedsin the pigeon breast state are sown on soil in a tray, and reared in adark place for three to seven days. Although radicles come out in thisperiod of time, the leave which have first been developed grow further,so that the seedlings have much better developed leaves, compared to thedevelopment of the radicles.

[0007] Then the rice seeds in this developed state of sprout growth aremoved together with the tray from the dark place to a place with lightsuch as a greenhouse and allowed to grow according to the conventionalmethod.

[0008] However, in this method, a considerable time of soaking in wateris required before sprouting; the sprouted rice seeds generally shownon-uniform growth and tend to fall sick; and furthermore, the watercontaining the fungicidal or bactericidal agent used in the sproutingprocess is discarded to cause a pollution problem and a loss of thefungicidal or bactericidal agent.

[0009] In addition, the radicles which just came out of the rice seedsin this method are comparatively weak to chemical toxicity of aninsecticidal agent. If an insecticidal agent is used when the radiclesare still small, growth of the radicles is arrested by the toxicity sothat growth of rice seedlings is slow. Accordingly, an insecticidalagent can be used only after considerable development of the radicles.Then, the sprouted rice might be eaten by insects.

SUMMARY OF THE INVENTION

[0010] The present invention provides a rice seed coated with anagricultural chemical which rice seed is almost completely protectedfrom diseases and insects, can rapidly attain almost uniform and goodsprout and can grow into healthy seedling.

[0011] The present inventors have made investigation to find out thereasons for the above-mentioned various problems. The inventors havefound that immersion of rice seeds in water in a considerable time tilldevelopment of a sprout is necessary for sufficient absorption of waterinto the seeds through the husk in order to make the sprouting asuniform as possible; however, if the soaking time is too long, the workefficiency is bad and, on the other hand, if the soaking time is tooshort, the absorption of water is not uniform and the sprouting is notuniform among the seeds; meanwhile, if the husk is removed from seeds,soaking in water is unnecessary, but mold will grow intensely duringsprouting to cause death of more than 50% of the seeds during thesprouting; and further, if radicles are made to first emerge beforecoleoptile do, the radicles are more resistant to an insecticidal agentthan in a conventional method, the insecticidal agent can be applied bysimultaneous coating together with a fungicidal or bactericidal agent,and then the insecticidal agent can start exhibit its effectsimmediately after sprouting.

[0012] Based on these pieces of knowledge, the inventors have made thefollowing invention. Thus, the invention is a rice seed coated with anagricultural chemical, characterized in that a rice seed is deprived ofhusk and the surface of said rice seed is coated with a bindercontaining an agricultural chemical.

[0013] Japanese Patent No. 2,866,921 discloses non-diseased brown riceseeds with an artificial coat, characterized in that rice seeds arede-husked to remove the husk in which infectious fungi or bacteria mightlie, washed with water to obtain almost sterile brown rice, which arethen coated, without being disinfected by agricultural chemicals, on thesurface with an artificial coat. It is essential in that patent thatde-husked rice seeds are washed with water to prevent germs attached tothe husk from contaminating the brown rice seeds and that the de-huskedrice seeds are not sterilized with an agricultural chemical in order toreduce the amount of agricultural chemicals to be used as much aspossible. Meanwhile in the present invention, it is not essential thatde-husked rice seeds are washed or soaked. The surface of the de-huskedbrown rice seeds are covered with an agricultural chemical. Since thesurface of the brown rice seeds is disinfected by an agriculturalchemical covering the surface of the rice seeds, washing after removingthe husk becomes unnecessary.

[0014] In the above-mentioned patented invention, disease germs presentin or on the husk are removed because the husk is removed from the seed.However, disease germs infectious to rice seeds exist not only in huskbut in soil, water, air, etc. Therefore, it is necessary to cope withthe disease germs after sowed in soil in a conventional manner which ispreviously practiced. Meanwhile in the present invention, the surface ofthe de-husked rice seeds is covered with an agricultural chemical and,therefore, all of disease germs present in or on the husk, and diseasegerms present in soil, water, air, etc. can be coped with.

[0015] Therefore, unlike the above-mentioned patented invention, thepresent invention has an advantage that no further treatment for copingwith a disease germ is necessary. As a result, even though the de-huskedrice seeds are covered with agricultural chemicals, the total amount ofthe agricultural chemicals used is less.

PREFERRED EMBODIMENTS OF THE INVENTION

[0016] In a preferred embodiment, the rice seed after de-husked is notwashed.

[0017] In another embodiment, the rice seed is selected from the groupconsisting of Oryza sativa sp. japonica, Oryza sativa sp. javanica,Oryza sativa sp. indica, and hybrids thereof

[0018] In another embodiment, the agricultural chemical is selected fromthe group consisting of fungicidal agents, bactericidal agents andinsecticidal agents.

[0019] In another embodiment, the fungicidal or bactericidal agent isapplied in an amount of 0.1 to 10 g per kg of the de-husked rice.

[0020] In another embodiment, the insecticidal agent is applied in anamount of 3 to 20 g per kg of the de-husked rice.

[0021] In another embodiment, the fungicide is selected from the groupconsisting of phenylpyrrole fungicides, azole fungicides, andstrobilurine fungicides.

[0022] In another embodiment, the insecticide is selected from the groupconsisting of neo-nicotinide insecticides, carbazates insecticides,pyrethroid ether insecticides, and pyridine azomethine insecticides.

[0023] In another embodiment, the binder is selected from the groupconsisting of polyvinyl acetates, polyvinyl alcohols, and polyvinylpyrrolidones.

[0024] In another embodiment, the binder is a mixture of 0 to 50% byweight of polyurethane and 100 to 50% by weight of polyvinyl alcohol.

[0025] In another embodiment, the rice seed is to be germinated bykeeping the seed under aerobic conditions which lead to emergence of aradicle first before emergence of a coleoptile.

[0026] In another embodiment, the rice seed is to be germinated bymaintaining the seed for at least three days at 20 to 40 degrees C.

[0027] In another embodiment, the rice seed is to be germinated bymaintaining the seed for 4 to 9 days at 25 to 35 degrees C.

[0028] In another embodiment, the rice seed is to be germinated bymaintaining the seed for 4 to 9 days around 30 degrees C.

[0029] The invention also provides a method of germinating the seeds asdescribed above, wherein the seeds are kept in aerobic conditions whichlead to emergence of a radicle first, before emergence of a coleoptile.

[0030] Any rice may be used, but is preferably selected from the groupconsisting of Oryza sativa sp. japonica, Oryza sativa sp. javanica,Oryza sativa sp indica, and hybrids thereof.

[0031] There is no particular limitation on a method of removing huskfrom rice seeds in the invention, as long as rice seeds are not brokenor greatly impaired. Any known method may be used. For example, twinrolls are used to remove husk. More specifically, for example, intactrice seeds are passed between twin rolls with a predetermined gapbetween the rolls, one of which rolls has a rotation speed and arotation direction different from those of the other roll. Then,suitable friction takes place between the twin rolls and the intact riceseeds to remove the husk from the rice seeds. If husk is not completelyremoved from the rice seeds by the above-mentioned operation, the riceseeds are again passed between twin rolls. The rotation speed and thegap of the twin rolls here may be the same as or different from those ofthe first pass. The rotation speeds and gaps may be suitably determinedby those having ordinary skill.

[0032] Commercially available twin rolls can be used such as, forinstance, MP, MPS and MPC series, such as MPS50, MP50, MP40, MPC40 andMPC35 ( trademarks, ex Iseki & Co., Ltd.), LTA series such as LTA10,LTA15, LTA20 and LTA30 (trademarks, ex Iseki & Co., Ltd.), MX seriessuch as M-300 Pearlmate (trademark, ex Iseki & Co., Ltd.), 5HP seriessuch as SY3700D, SY3700DC and NR3700SD (trademarks, ex Yammar DieselEngine, Inc.), and HT10PP, HR10PN, HR10N and THU35A (trademarks, exSatake, Inc.).

[0033] The de-husked rice seeds show rapid and uniform absorption ofwater and can germinate in a relatively wide range of temperature,compared to intact rice seeds with husk. The brown rice seeds with nohusk are preferably stored at a temperature of 15 to 25 degrees C. inair with a relative humidity of 30 to 40%, before and after coated withthe binder containing an agricultural chemical.

[0034] As the agricultural chemicals, use may be made of fungicidal andbactericidal agents, insecticidal agents, biocides, disinfectants andbiological organisms beneficial to control pathogens, preferablyfungicidal or bactericidal agents, and insecticidal agents. Any knownfungicidal or bactericidal agents and insecticidal agents may be.

[0035] Examples of the fungicidal or bactericidal agents may includephenylpyrrole fungicides, such as fenpiclonil and fludioxonil, azolefungicides such as triflumizol, propiconazole and tebuconazole, andstrobilurine fungicides such as azoxystrobin. Those commerciallyavailable include Rovral (trademark, ex Rhone-Poulenc), Ridomyl MZ(trademark, ex Novartis Agro), Healthied (trademark, ex Kube), TrifmineWP (trademark, ex Nissan Chemical Industries, Ltd.), Homai and Homaicoat(trademarks, ex Nippon Soda Co., Ltd.), Benlate-T and Benlate 50 WP(trademark, ex Du Pont); Thionock 50, Daconil, Kes, Spaglin, Dacolateand Orthocide (trademarks); and Savior (trademark, ex Novartis Agro).More preferably used are Rovral, Ridomyl MZ, Healthied, Trifmine WP andSavior.

[0036] The insecticidal agent include neo-nicotinide insecticides suchas imidacloprid, acetamiprid and thiametoxam, carbazates insecticidessuch as bifenazate, pyrethroid ether insecticides such as etofenprox andflufenprox, and pyridine azomethine insecticides such as pymetrozine.Commercially available products include Mospilan (trademark, ex NipponSoda Co., Ltd.), Actara and Cruiser (trademarks, ex Novartis Agro),Trebon (trademark, ex Mitsui Chemical), Gaucho, Admire, Confidor andProvado (trademarks, ex Nihon Bayer), Best Guard (TI-435) (trademark, exTakeda Chemical Industries, Ltd.), and AKD-1022 (trademark, exAgro-Kanesho). Baidit2, Baidit3 and Padan WS (trademarks) may also beused.

[0037] The biocides include Acticide 45, Acticide CSP, and Acticide EW(trademarks, ex Thor Industries), for which more information isavailable at www.thor-chemicals.com. The disinfectants include alcohols,sodium hypochlorite, and potassium or sodium triphosphate. Thebiological organisms beneficial to control pathogens include Trichodermaharzianum, Bacillus subtillus, and Gliocladium virens, for which moreinformation is available at www.bioworksbiocontrol.com.

[0038] The quantity of the fungicidal or bactericidal agent and thequantity of the insecticidal agent to be applied depend on a type ofthose agents. The fungicidal or bactericidal agent is applied to therice seed surface preferably in a ratio of 0.1 to 10 grams, morepreferably 0.5 to 2 grams, per kilogram of the brown rice seeds fromwhich husk has been removed. The insecticidal agent is applied to therice seed surface preferably in a ratio of 3 to 20 grams, morepreferably 5 to 10 grams, per kilogram of the brown rice seeds fromwhich husk has been removed. When the fungicidal or bactericidal agentand the insecticidal agent which are preferably of slow release orlag-burst release are used in the above-mentioned ranges, the effectsare maintainable over 2 to 4 months after sowing. Conventionally, aperiod of continuous effectiveness is about 2 weeks for usual fungicidalor bactericidal agents, or 2 to 4 months for special fungicidal orbactericidal agents; and about 2 months for insecticidal agents.According to the present invention, a period of the continuouseffectiveness is generally prolonged, compared to the above-mentionedconventional manner.

[0039] The biocide and the disinfectant are each applied to thede-husked rice seed surface preferably in a ratio of 0.1 to 10 grams,more preferably 0.5 to 2 grams, per kilogram of the brown rice seedsfrom which husk has been removed. The amount of the biological organismbeneficial to control pathogens is preferably 1×10⁷ to 1×10¹⁰ CFU, morepreferably 5×10⁸ to 5×10⁹ CFU, per kilogram of the brown rice seeds fromwhich husk has been removed. Here, “CFU” or colony forming unit is abiable count of the organism in question when the organism is culturedon an agar medium in a petri-dish.

[0040] In addition to the above-mentioned fungicidal or bactericidalagent and the insecticidal agent, the surface of the brown rice seed ofthis invention may be provided with other substances such as, forexample, rodent killing agents, weed killers, attracting agents,repellent agents, plant growth regulators such as giberillic acid,auxine and citokinine, nutrients such as potassium nitrate, magnesiumsulphate, and iron gelate, plant hormones, pigments, fillers, wax,oxidizing or anti-oxidation agents, activated carbon, surface-activeagents, spreaders, gene activators such as BRX-156 (ex Biorex), systemicresistance activators such as Bion (Acebenzolar-S-methyl, ex NovartisAgro), and Messenger( Harpin protein, ex Cornel University, EdenBioscience), plant growth promotors such as Grow Ace (fungi extract, exSnowbrand), and Tachigare (NEB-glycoside, ex Sankyo Chemical), andothers including chitosan (chitin-based polymer), seed weed extracts,plant extracts, and minerals.

[0041] A binder is used to bind the above-mentioned fungicidal orbactericidal agent and the insecticidal agent onto the brown rice seedfrom which husk has been removed. Any known binder can be used. If wateris used as a solvent, use is preferably made of water-soluble binders,or water-emulsifiable or -dispersible binders. Examples of the bindersinclude polyvinyl acetate, polyvinyl alcohol, carboxy methyl cellulose,methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethylcellulose, cellulose polymer, chitin, polyvinylidene chloride,water-dispersible polyacrylic resins, polysodium acrylate,polyacrylamide, acrylate copolymers, polyvinyl pyrrolidone,polyurethane, polysaccharides, starch, and gum type binders. Preferredare polyvinyl acetate, polyvinyl alcohol, polyvinyl pyrrolidone,water-dispersible polyacrylic resins, and polyurethane. These bindersmay be used alone or in combination of two or more of these.

[0042] The fungicidal or bactericidal agent and the insecticidal agentconfined in the binder come to exhibit their effects gradually onaccount of the binder, so that the effects are maintained for aprolonged period. It is possible to combine a plurality of the binders,such as polyvinyl alcohol and polyurethane. A release rate of thefungicidal or bactericidal agent and the insecticidal agent canpreferably be controlled, using a binder mixture comprising 0 to 50% byweight of polyurethane and 100 to 50% by weight of polyvinyl alcohol.

[0043] Although the amount of the binder to be applied to the rice seedsurface depends somewhat upon the kind of the binder, it may be 0.3 to30 g, usually 0.5 to 10 g, more preferably 1 to 6 g, per kg of the brownrice seeds from which husk has been removed. For example, 1 kg of thebrown rice seeds from which husk has been removed is provided preferablywith 1 to 20 g, more preferably 2 to 10 g, most preferably 3 to 6 g, ofpolyvinyl acetate; 0.3 to 20 g, more preferably 0.5 to 4 g, mostpreferably 1 to 2 g, of polyvinyl alcohol; 0.5 to 14 g, more preferably1 to 7 g, most preferably 2 to 4 g, of hydroxypropyl methyl cellulose;or 0.5 to 12 g, more preferably 1 to 6 g, most preferably 1.5 to 3 g, ofpolyvinyl pyrrolidone. Below the aforesaid lower limits, it is difficultto provide the brown rice seeds with the required amounts of thefungicidal or bactericidal agent and the insecticidal agent in goodconditions.

[0044] In this invention, a method of coating the surface of thede-husked brown rice seeds with the fungicidal or bactericidal agentand/or the insecticidal agent is not particularly limited, and any knownmethod can be used. For instance, the fungicidal or bactericidal agentand/or the insecticidal agent and the binder are dissolved, emulsifiedor dispersed in a solvent, preferably water, to obtain a solution,emulsion or dispersion, which is then sprayed on the de-husked brownrice seeds or in which the de-husked brown rice seeds are soaked. Thespraying is preferred. As a spray-coating equipment, use may be made ofrotation granulator type coating machines, such as type 9300.00.00,9310.00.00, 9320.00.00, and 9330.00.00, ex Seed Processing Holland;Satec Concept 3.10, ex Cimbria Heid GmbH, Austria; Centricoater CC20, exWilly Niklas, Germany; and W.N.5/500, ex Gustaphson, U.S.A.

[0045] Subsequently, the rice seeds coated with the fungicidal orbactericidal agent and/or the insecticidal agent as mentioned above aredried. In order to maintain the good quality of the coated rice seeds,the seeds are preferably dried in air preferably at 30 to 50 degrees C.,preferably until they reach an equilibrium at a relative humidity of 30to 40%.

[0046] The agricultural chemical-coated rice seeds of the invention thusobtained are then sowed on soil in a tray which may be such currentlyused for the sprouting of usual rice seeds, and are maintained under thefollowing conditions for sprouting.

[0047] In the invention, the rice seeds covered with the agriculturalchemicals are germinated in aerobic conditions where radicles willemerge before coleoptiles emerge. The aerobic conditions herein meanthat an oxygen concentration in the atmosphere near the surface of thecoating on the rice seeds is preferably at least 1.0% by volume, morepreferably at least 3.0% by volume, further preferably at least 5.0% byvolume. When the rice seed is covered with soil, the oxygenconcentration refers similarly to that of the atmosphere near thesurface of the coating, but oxygen contained in the soil is not takeninto consideration. If sprouting is carried out in an anaerobicatmosphere with an oxygen concentration less than the above-mentionedlower limit, for example, in underwater conditions as previous where theoxygen concentration is about 5 to 15 p.p.m. at atmospheric pressure at20 to 30 degrees C., development of coleoptiles from the seed is muchremarkable, compared to development of radicles, and the growth is notuniform among seeds, which is undesirable.

[0048] In the case of the rice seed of this invention covered with thefungicidal or bactericidal agent and/or the insecticidal agent, if anatmosphere near the surface of the coating on the seeds is maintained inaerobic conditions, the inside of the coating, i.e., the surface of thede-husked rice is also held in aerobic conditions. Therefore,development of radicles is rapid and remarkable, without non-uniformityin sprouting, much more than development of coleoptiles, and seedlingsgrow well and healthily.

[0049] The above-mentioned aerobic conditions are maintained preferablyat 20 to 40 degrees C., more preferably 25 to 35 degrees C.,particularly preferably 30 to 35 degrees C. usually for a period of froma time when the rice seed is sowed on soil to a time when it germs viaembryogenesis, preferably for at least 3 days, more preferably 4 to 9days, whereby sprouting of the rice seeds can be promoted and can bemade more uniform.

[0050] The rice seeds after sowed can be preferably covered withvermiculite. It is possible to conduct usual agricultural-chemicalsprocessing on the soil after the sowing. Such a degree of sprinkling ofwater after the sowing that the soil remains humid is enough. Irrigationwater after the sowing is applied to such extent that the soil remainssufficiently humid. If excessive water is applied or the seeds aresubmerged under water, it is difficult to maintain aerobic conditions,and anaerobic conditions take place easily, which should be avoided.According to the invention, it is not necessary to store the rice seedsin a dark place, unlike conventional intact rice seeds covered withagricultural chemicals, and then can be put under day lights togerminate.

[0051] The rice seeds thus sprouted are cultivated and brought upaccording to a usual manner.

[0052] The present invention provides a rice seed coated with anagricultural chemical which rice seed is almost completely protectedfrom diseases and insects, can rapidly attain almost uniform and goodsprout and can grow into healthy seedling. The present rice seed doesnot require soaking in water containing a bactericide or fungicide,which soaking is needed for germinating conventional rice seeds coatedwith an agricultural chemical. Therefore, there is no pollution problemor economical problem caused by discarding the water containing anagricultural chemical. It is unnecessary to circulate water duringgermination any more. Labor of keeping seeds in a dark place for apredetermined time period after germination is unnecessary at all.Radicles which come out prior to coleoptiles are resistant tophytotoxicity of insecticides and, therefore, even if seeds are coveredwith an insecticide together with a bactericide, growth of the radiclesis not hindered, unlike in the conventional case. In the present seeds,absorption of water can be controlled by the coating and uniform watercontent is maintained. Further, an oxygen concentration on the surfaceon the de-husked seeds can be properly adjusted by the coating, andoxidation of the seeds during storage can be avoided. In addition, thepresent rice seeds are de-husked and, therefore, are not an object toimport restriction, so that one may de-husk rice in a foreign countrywhich is then imported and give the coating in a home country, or onemay de-husk rice and give the coating in a foreign country, which isthen imported. Thus, one may have more choices on kinds of rice seedsand can prepare seeds with less costs.

[0053] In large scale of rice production, rice seeds are sown in paddyfields by an airplane. In order to avoid that the sown seeds float onthe water surface and float about by wind or water currents, the seedsare made to adsorb sufficient water in advance. Job of this adsorptionrequires a lot of time and labor. The present rice seeds do not float inwater. In addition, they are smaller and lighter than intact seeds, sothat an airplane can carry a larger amount of the seeds for moreefficient sowing job. Thus, the present rice seeds are suitable to beair-sown.

[0054] The invention will be explained below in more detail withreference to the Examples which shall not be construed to limit theinvention.

CONTROL EXAMPLE 1

[0055] Intact rice seeds, KOSHIHIKARI, were processed by twin rolls,MX-300 Pearlmate, (trademark, ex Iseki & Co., Ltd.) to remove the husk.

[0056] Subsequently, coating liquid A as indicated in the followingTable 1 was sprayed on the de-husked rice seeds at room temperaturewithout washing the de-husked rice seeds with water or others, and driedto obtain the de-husked rice seeds coated with a polyvinyl acetatebinder. A rotor-granulator type coating machine, model 9320.00.00(exSeed Processing Holland) was used in the spraying, and the drying wascarried out in a relative humidity of 30% in an air flow of atemperature of 30 to 40 degrees C.

[0057] The amount of coating liquid A used was 40 g per kg of thede-husked rice seeds. The quantity of the polyvinyl acetate binderapplied to the surface of the de-husked rice seeds was 4.8 g per kg ofthe de-husked rice seeds. TABLE 1 Coating Liquid A Component Content, %by weight Polyvinyl acetate (binder) 12.0 Water 88.0

[0058] Each 100 grains of the intact rice seeds, the de-husked riceseeds and the de-husked rice seeds processed with coating liquid A wereeach sown on filter paper (ex Schleicher & Schuel) folded into 50 foldsin a plastic container and wetted with 60 cc of water. Under thisaerobic condition, they were kept in a dark place at a temperature of 20degrees C. for 16 hours and then in the light at a temperature of 30degrees C. for 8 hours, which operation was repeated for ten days(hereinafter referred to as Condition 1). Then, it was observed with thenaked eye whether the sprouted and grown seedlings were healthy or not.

[0059] The results are as seen in Table 2. TABLE 2 State of theSeedlings Percentage of Seed Healthy Seedlings Intact rice seeds 64%De-husked brown rice seeds 78% De-husked brown rice seeds processed withcoating 94% liquid A

[0060] As seen above, the brown rice seeds which were de-husked andprocessed with coating liquid A, i.e., covered with a polyvinyl acetatebinder, gave a larger number of healthy seedlings in Condition 1,compared to the intact rice seeds or the simply de-husked rice seeds.

EXAMPLE 1

[0061] Coating liquid B as indicated in the following Table 3 wassprayed on the de-husked rice seeds prepared as in Control Example 1above, without washing the de-husked rice seeds with water or others,and dried to obtain the de-husked rice seeds coated with a polyvinylacetate binder containing the insecticide, imidacloprid. The spraycoating and drying were carried out as in Control Example 1 above.

[0062] The amount of coating liquid B used was 56 g per kg of thede-husked rice seeds. The quantities of imidacloprid and the polyvinylacetate binder applied to the surface of the de-husked rice seeds were5.6g and 4.8 g, respectively, per kg of the de-husked rice seeds. TABLE3 Coating Liquid B Component Content, % by weight Gaucho 70WS * 14.3Polyvinyl acetate (binder) 8.6 Water 77.1

[0063] Each 100 grains of the intact rice seeds, the de-husked riceseeds processed with coating liquid A and the de-husked rice seedsprocessed with coating liquid B were each sown on soil in a pot. Underthis aerobic condition, they were kept in a dark place at a temperatureof 30 degrees C. for 3 days and then in the light at a temperature of 20degrees C. for 10 days (hereinafter referred to as Condition 2). Then,for possible phytotoxicity caused by imidacloprid, it was observed withthe naked eye whether the sprouted and grown seedlings were healthy ornot.

[0064] The results are as seen in Table 4. TABLE 4 State of theSeedlings Percentage of Seed Healthy Seedlings Intact rice seeds 77%De-husked brown rice seeds processed with coating 75% liquid A De-huskedbrown rice seeds processed with coating 75% liquid B

[0065] As seen above, the rate of the healthy seedlings from thede-husked brown rice seeds processed with coating liquid A sprouted inCondition 2 is less than that in Condition 1, but is almost same as thatof the intact seeds in Condition 2. In Condition 2, the rate of thehealthy seedlings from the de-husked brown rice seeds processed withcoating liquid B is same as that from the de-husked brown rice seedsprocessed with coating liquid A, which means that there is almost nophytotoxicity by imidacloprid and good sprouting comparable to intactseeds are attained.

EXAMPLE 2

[0066] Intact rice seeds, AKITAKOMACHI, were processed by twin rolls,MX-300 Pearlmate, (trademark, ex Iseki & Co., Ltd.) to remove the husk.

[0067] Coating liquid C as indicated in the following Table 5 wassprayed on the de-husked rice seeds prepared above, without washing thede-husked rice seeds with water or others, and dried to obtain thede-husked rice seeds coated with a binder. The spray coating and thedrying were carried out as in Control Example 1 above.

[0068] The amount of coating liquid C used was 69 g per kg of thede-husked rice seeds. The quantities of pefurazoate (bactericidalagent), imidacloprid (insecticide) and the polyvinyl acetate binderapplied to the surface of the de-husked rice seeds were 0.2 g, 11.2 gand 4.8 g, respectively, per kg of the de-husked rice seeds. TABLE 5Coating Liquid C Component Content, % by weight Healthied 20 * 1.4Gaucho 70WS ** 23.2 Polyvinyl acetate (binder) 7.0 Water 68.4

[0069] Each 100 grains of the intact rice seeds, the de-husked riceseeds, the de-husked rice seeds processed with coating liquid A and thede-husked rice seeds processed with coating liquid C were sown on eachfilter paper (ex Schleicher & Schuel) which were folded into 50 folds ina plastic container and wetted with 60 cc of water. Under this aerobiccondition, they were kept in a dark place at a temperature of 20 degreesC. for 16 hours and then in the light at a temperature of 30 degrees C.for 8 hours, which operation was repeated for seven days (hereinafterreferred to as Condition 3). Then, it was observed with the naked eyewhether the sprouted and grown seedlings were healthy or not.

[0070] The results are as seen in Table 6. TABLE 6 State of theSeedlings Percentage of Seed Healthy Seedlings Intact rice seeds 78%De-husked brown rice seeds 89% De-husked brown rice seeds processed withcoating 95% liquid A De-husked brown rice seeds processed with coating95% liquid C

[0071] In Condition 3 here, the operation was repeated for 7 days,instead of 10 days in Condition 1. AKITAKOMACHI rice seeds were usedhere. The brown rice seeds which were de-husked and processed withcoating liquid A, i.e., covered with a polyvinyl acetate binder, gave alarger number of healthy seedlings in Condition 3, compared to theintact rice seeds or the simply de-husked rice seeds. These results aresame as those in the experiments in Condition 1. The rate of the healthyseedlings from the de-husked brown rice seeds processed with coatingliquid C, i.e., covered with the polyvinyl acetate binder, bactericidepefurazoate and insecticide imidacloprid, is larger than those from theintact rice seeds and from the de-husked rice seeds, and almost same asthat from the de-husked brown rice seeds processed with coating liquidA. Thus, good sprouting was attained without phytotoxicity.

EXAMPLE 3

[0072] Example 2 was repeated with the exception that the followingcoating liquid D was used.

[0073] The amount of coating liquid D used was 69 g per kg of thede-husked rice seeds. The quantities of pefurazoate (bactericidalagent), imidacloprid (insecticide) and the polyvinyl acetate binderapplied to the surface of the de-husked rice seeds were 0.2 g, 11.2 gand 2.0 g, respectively, per kg of the de-husked rice seeds. TABLE 7Coating Liquid D Component Content, % by weight Healthied 20 * 1.4Gaucho 70WS ** 23.0 Polyvinyl pyrrolidone (binder) 2.9 Water 72.5

[0074] The state of sprouting was observed in Condition 3 as in Example2. Then, it was observed with the naked eye whether the sprouted andgrown seedlings were healthy or not.

[0075] The results are as seen in Table 8. TABLE 8 State of theSeedlings Percentage of Seed Healthy Seedlings De-husked brown riceseeds processed with coating 96% liquid D

[0076] The rate of the healthy seedlings from the de-husked brown riceseeds processed with coating liquid D, i.e., covered with the polyvinylpyrrolidone binder, bactericide pefurazoate and insecticideimidacloprid, is larger than those from the intact rice seeds and fromthe de-husked rice seeds, and almost same as that from the de-huskedbrown rice seeds processed with coating liquid A. Thus, good sproutingwas attained without phytotoxicity.

EXAMPLE 4

[0077] Coating liquid E as indicated in the following Table 9 wassprayed on the de-husked rice seeds prepared as in Control Example 1above, without washing the de-husked rice seeds with water or others,and dried to obtain the de-husked rice seeds coated with a polyvinylpyrrolidone binder containing a bactericide, fludioxonil. The spraycoating and the drying were carried out as in Control Example 1 above.

[0078] The amount of coating liquid E used was 41 g per kg of thede-husked rice seeds. The quantities of fludioxonil and the polyvinylpyrrolidone binder applied to the surface of the de-husked nice seedswere 0.2 g and 2 g, respectively, per kg of the de-husked rice seeds.TABLE 9 Coating Liquid E Component Content, % by weight Savior * 2.4Polyvinyl pyrrolidone (binder) 4.9 Water 92.7

[0079] Each 100 grains of the de-husked rice seeds and the de-huskedrice seeds processed with coating liquid E were sprouted and grown inCondition 1. Then, it was observed with the naked eye whether thesprouted and grown seedlings were healthy or not.

[0080] The results are as seen in Table 10. TABLE 10 State of theSeedlings Percentage of Seed Healthy Seedlings De-husked brown riceseeds 78% De-husked brown rice seeds processed with coating 91% liquid E

[0081] As seen above, the rate of the healthy seedlings from thede-husked brown rice seeds processed with coating liquid E is largerthan that from the de-husked rice seeds, which means that there isalmost no phytotoxicity by fludioxonil and better sprouting than thatfrom the de-husked rice seeds is attained.

EXAMPLE 5

[0082] Example 4 was repeated with the exception that coating liquid Findicated in the following coating Table 11 was used.

[0083] The amount of coating liquid F used was 48.85 g per kg of thede-husked rice seeds. The quantities of fludioxonil (bactericidalagent), thiametoxam (insecticide) and a polyvinyl pyrrolidone binderapplied to the surface of the de-husked rice seeds were 0.2 g, 5.5 g and2.0 g, respectively, per kg of the de-husked rice seeds. TABLE 11Coating Liquid F Component Content, % by weight Savior * 2.0 Cruiser **16.1 Polyvinyl pyrrolidone (binder) 4.1 Water 77.8

[0084] The state of sprouting was investigated as in Example 4. Thus, itwas observed with the naked eye whether the sprouted and grown seedlingswere healthy or not.

[0085] The results are as seen in Table 12. TABLE 12 State of theSeedlings Percentage of Seed Healthy Seedlings De-husked brown riceseeds processed with coating 88% liquid F

[0086] The rate of the healthy seedlings from the de-husked brown riceseeds processed with coating liquid F, i.e., covered with the polyvinylpyrrolidone binder, bactericide fludioxonil and insecticide thiametoxam,is larger than that from the de-husked rice seeds, which means thatthere is almost no phytotoxicity by fludioxonil or by thiametoxam andbetter sprouting than that from the de-husked rice seeds is attained.

EXAMPLE 6

[0087] The rice seeds as prepared in Examples 4 and 5 and the de-huskedseeds were subjected to the following germination tests.

[0088] 150 Milliliters of soil (particulate soil for cultivation,produced by Kumiai, sold by JA) were put in a tray of 200 ml. Each 100grains of the aforesaid seeds were sown in each tray and covered with 20ml of the aforesaid soil, to which 50 ml of water was then added. Underthis aerobic condition, they were kept in a dark place at a temperatureof 30 degrees C. for 3 days and then in the light at a temperature of 20degrees C. for 7 days to be germinated. Then, growth of the seedlingsand formation of mold were observed with the naked eye.

[0089] The results are as seen in Table 13. TABLE 13 State of theSeedlings Formation of Seed Mold Growth of the Seedling De-husked brownrice seeds Remarkable Usual Seeds prepared in Example 4 No Good Seedsprepared in Example 5 No Good

[0090] Next, the rice seeds coated each with coating liquids A through Fas in Control Example 1 and Examples 1 through 5 were cultivatedaccording to a conventional manner where neither insecticide norbactericide was sprinkled. As a result, the rice seeds coated withcoating liquids B through F showed good growth, but the rice seedscoated with coating liquid A, i.e., coated by a binder alone showedsevere damages by insects and diseases and the growth was impeded.

EXAMPLE 7 and COMPARISON EXAMPLE 1

[0091] In Example 7, coating liquid G as indicated in the followingTable 14 was sprayed on the de-husked rice seeds prepared as in ControlExample 1 above, without washing the de-husked rice seeds with water orothers, and dried to obtain the de-husked rice seeds coated with apolyvinyl alcohol binder containing the bactericide, fludioxonil.

[0092] The amount of coating liquid G used was 41 g per kg of thede-husked rice seeds. The quantities of fludioxonil and the polyvinylalcohol binder applied to the surface of the de-husked rice seeds were0.2 g and 2 g, respectively, per kg of the de-husked rice seeds. TABLE14 Coating Liquid G Component Content, % by weight Savior * 2.4Polyvinyl alcohol (binder) 4.9 Water 92.7

[0093] Meanwhile in Comparison Example 1, the de-husked rice seeds asprepared in Control Example 1 were washed with flowing tap water for 2hours. Coating liquid H consisting of 5% by weight of the polyvinylalcohol binder and 95% by weight of water was sprayed on the rice seeds,and dried to obtain the de-husked rice seeds coated with a polyvinylalcohol binder alone. The amount of coating liquid H used was 40 g perkg of the de-husked rice seeds. The quantity of the polyvinyl alcoholbinder applied to the surface of the de-husked rice seeds was 2 g, perkg of the de-husked rice seeds. Both in Example 7 and Comparison Example1, the spray coating and the drying were carried out as in ControlExample 1.

[0094] Each 100 grains of the intact rice seeds, the de-husked riceseeds and the two types of the de-husked rice seeds processed above weresown on soil in each pot. Under this aerobic condition, they were keptin a dark place at a temperature of 20 degrees C. for 16 hours and thenin the light at a temperature of 30 degrees C. for 8 hours, whichoperations was repeated for 8 days (hereinafter referred to as Condition4). Then, growth of the seedlings and formation of mold were observedwith the naked eye.

[0095] The results are as seen in Table 14. TABLE 14 State of theSeedlings Formation of Growth of the Seed Mold Seedling Intact riceseeds No Good De-husked brown rice seeds A little Very good Seedsprepared in Example 7 No Very good Seeds prepared in Com. Example 1Remarkable Good

[0096] In Example 7 where the rice seeds were coated with the polyvinylalcohol containing the bactericide, the growth of the seedlings was verygood and no formation of mold was observed at all. Meanwhile, inComparison Example 1, which follows Japanese Patent No. 2,866,921, thegrowth of the seedlings was poorer than that in Example 7 and theformation of mold was remarkable, which apparently adversely affects thegrowth of the seedlings in future development.

[0097] It is believed that a reason why mold occurs remarkably inComparison Example 1 is that removal of husk causes fine flaws on thesurface of the seeds; the flaws are enlarged by the water washing forasepsis; a lot of saccharides come out through the enlarged flaws, whichare utilized by mold for proliferation. In contrast, in Example 7, nowater washing take place and, therefore, no enlargement of flaws takeplace.

EXAMPLE 8

[0098] Coating liquids I, J and K as indicated in the following Tables15, 16 and 17 were each sprayed on the de-husked rice seeds prepared asin Control Example 1 above, without washing the de-husked rice seedswith water or others, and dried to obtain three types of the de-huskedrice seeds coated with a polyvinyl alcohol with different amounts ofpolyurethane, containing an insecticide, imidacloprid. The spray coatingand the drying were carried out as in Control Example 1 above.

[0099] The amounts of coating liquids I, J and K used was each 47.77 gper kg of the de-husked rice seeds. The quantity of imidacloprid appliedto the surface of the de-husked rice seeds was always 5.5 g per kg ofthe de-husked rice seeds. The quantity of the binder is 3.92 g of thepolyvinyl alcohol and 0 g of the polyurethane with coating liquid I;3.53 g of the polyvinyl alcohol and 0.39 g of the polyurethane withcoating liquid J; and 2.94 g of the polyvinyl alcohol and 0.98 g of thepolyurethane with coating liquid K, per kg of the de-husked rice seeds.TABLE 15 Coating Liquid I Component Content, % by weight Gaucho 70WS *16.4 Polyvinyl alcohol (binder) 8.2 Polyurethane (binder) 0 Water 75.4

[0100] TABLE 16 Coating Liquid J Component Content, % by weight Gaucho70WS * 16.4 Polyvinyl alcohol (binder) 7.4 Polyurethane (binder) 0.8Water 75.4

[0101] TABLE 17 Coating Liquid K Component Content, % by weight Gaucho70WS * 16.4 Polyvinyl alcohol (binder) 6.2 Polyurethane (binder) 2.0Water 75.4

[0102] Each 5 g of the de-husked rice seeds thus processed with coatingliquid I, J or K were placed on each petri-dish, to which 10 ml of waterwere poured. After a predetermined period of time at room temperature, aconcentration of imidacloprid in the water was determined by liquidchromatography.

[0103] The results are as seen in Table 18. TABLE 18 Released amount ofimidacloprid, by weight * Type of the coating liquid Time, hour I J K 18.8 2.7 1.9 2 11.4 4.3 3.5 4 15.7 7.3 5.9 6 21.1 10.0 8.1 24 38.0 29.428.0

[0104] It is seen from the above results that when polyurethane is usedin addition to polyvinyl alcohol, a releasing rate of imidacloprid intowater is decreased. That is, the released amount in the case of the riceseeds processed with coating liquid K containing polyurethane is 8.1% byweight at 6 th hour, while that in the case of the rice seeds processedwith coating liquid I containing no polyurethane is 8.8% by weightalready at 1st hour.

1. A rice seed coated with an agricultural chemical, characterized in that a rice seed is deprived of husk and the surface of said rice seed is coated with a binder containing an agricultural chemical.
 2. The rice seed as claimed in claim 1, wherein said rice seed after de-husked is not washed.
 3. The rice seed as claimed in claim 1 or 2, wherein said rice is selected from the group consisting of Oryza sativa sp. japonica, Oryza sativa sp. javanica, Oryza sativa sp. indica, and hybrids thereof.
 4. The rice seed as claimed in any one of claims 1 to 3, wherein said agricultural chemical is selected from the group consisting of fungicidal agents, bactericidal agents and insecticidal agents.
 5. The rice seed as claimed in claim 4, wherein a fungicidal or bactericidal agent is applied in an amount of 0.1 to 10 g per kg of the de-husked rice.
 6. The rice seed as claimed in claim 4 or 5, wherein an insecticidal agent is applied in an amount of 3 to 20 g per kg of the de-husked rice.
 7. The rice seed as claimed in any one of claims 4 to 6, wherein the fungicide is selected from the group consisting of phenylpyrrole fungicides, azole fungicides, and strobilurine fungicides.
 8. The rice seed as claimed in any one of claims 4 to 7, wherein the insecticide is selected from the group consisting of neo-nicotinide insecticides, carbazates insecticides, pyrethroid ether insecticides, and pyridine azomethine insecticides.
 9. The rice seed as claimed in any one of claims 1 to 8, wherein the binder is selected from the group consisting of polyvinyl acetates, polyvinyl alcohols, and polyvinyl pyrrolidones.
 10. The rice seed as claimed in any one of claims 1 to 9, wherein the binder is a mixture of 0 to 50% by weight of polyurethane and 100 to 50% by weight of polyvinyl alcohol.
 11. The rice seed as claimed in any one of claims 1 to 10, wherein said rice seed is to be germinated by keeping the seed under aerobic conditions which lead to emergence of a radicle first before emergence of a coleoptile.
 12. The rice seed as claimed in claim 11, wherein said rice seed is to be germinated by maintaining the seed for at least three days at 20 to 40 degrees C.
 13. The rice seed as claimed in claim 11, wherein said rice seed is to be germinated by maintaining the seed for 4 to 9 days at 25 to 35 degrees C. 14 The rice seed as claimed in claim 11, wherein said rice seed is to be germinated by maintaining the seed around 30 degrees C.
 15. A method of germinating the seeds as claimed in any one of claim 1 to 10, wherein the seeds are kept in aerobic conditions which lead to emergence of a radicle first before emergence of a coleoptile. 